1. Field of the Invention
The present invention generally relates to a machine for washing scraps of fibrous materials, and more particularly, to a machine for washing scraps of fibrous material impregnated with resin so that the resin may be extracted with the use of appropriate solvents.
2. Discussion of Background
The use of fibrous materials such as fiberglass, carbon fiber, polyamide, or similar materials, that have been steeped in resin is common in the manufacture of numerous elements. In one known process, a thermostable matrix is placed on a mold surface and impregnated with resins. The resins are subsequently hardened, affording rigidity to the whole. The process gives rise to a light product with enough resistance for it to be suitable for various industrial purposes, among which are those concerned with the manufacture of containers capable of holding corrosive liquids.
Also quite frequent is the incorporation of reinforcements of fiberglass, carbon fiber, polyamide staple, and similar materials in the thermostable matrix, with an aim to affording sufficient structural rigidity for certain industrial purposes.
There exists fiberglass pre-impregnated with resins that facilitates the manufacturing process of components by means of the above-described process.
The manufacture of elements using fiberglass, carbon fiber, polyamide, or similar materials, placed on a mold and subsequently impregnated with resin, or using fiberglass preimpregnated with resin, generates a considerable amount of scrap, due to the need to cut the required shapes from the industrial fibrous sheets, especially fiberglass sheets, which are usually rectangular in shape.
The scraps from fiberglass, carbon fiber, polyamide, or similar materials, which have been impregnated with resin, form toxic waste which it is desirable to make inert. On the other hand, the possible separation of the resin from the thermostable matrix would allow the latter to be subsequently re-used and the reinforcements optionally present to be recovered.
It is known to separate the thermostable matrix from the resin it has been impregnated with, by washing with appropriate solvents, thus achieving one of the above-described objectives.
For ecological reasons and for reasons of economy in the industrial process involved in the manufacture of components with fiberglass, carbon fiber, polyamide, or similar materials pre-steeped in resin, an industrial machine which could carry out the above-described process is desirable. The applicant is unaware of the existence of any such machine to be used for such purposes.
The above-described object has been achieved by a machine including a closed, hollow container having one inlet and one outlet, the container enclosing at least one conveyor belt over which is situated at least one tank, wherein a drying means is installed at the end of the conveyor belt upstream of the output of the container.
The scraps are fed at the end of the conveyor belt located at the inlet of the container. The spraying machine sprays or the spraying machines spray solvent on the scrap placed on the belts thus, dissolving the resin, and the washed scraps are then dried inside of the container to prevent any flow of solvent vapor out of the container.
In a preferred embodiment, the machine includes a plurality of conveyor belts arranged in series over which a plurality of overhead spraying nozzles are situated. The conveyor belts are preferably inclined and drive the belt in the upper direction, in such a way that the upper end of a first conveyor belt feeds the lower end of the downstream conveyor belt.
In a most preferred embodiment, the machine includes a first washing section with a first belt section, optionally including a plurality of conveyors arranged in series, situated above a first tank formed by internal walls of the bottom part of the container, and at least a second washing section with a second belt section arranged in series with the first one, optionally including a plurality of conveyors, situated above a second tank formed by internal walls of the bottom part of the container and separated from the first one, an overhead spraying device being located above each of the conveyor belt sections. The shape of the bottom tanks is a parallelpiped.
Separation of the resins from the scraps of fibrous materials is achieved by the spray of solvent dissolving the resins, the used solvent being collected and subsequently stored in the tanks preferably placed for that purpose within the container.
The flow of solvent from the overhead spray machines is re-circulated from the tanks for that purpose within the container. The tank situated directly under the first conveyor belt section feeds the overhead spray machines that wash the conveyor belt or belts, while the scrap on the second conveyor belt section is washed by means of the solvent supplied by the tank for that purpose situated under the second section.
The possible loss of washing solvent is rectified by means of the addition of clean solvent to the process from a tank connected to the re-circulation circuit by suitable means.
In a preferred embodiment, the resin floating in the tank containing the solvent for washing the scrap in the downstream washing section or sections can be periodically transferred to a tank upstream, via an appropriate valve, thus completing the washing process carried out by the overhead spray machines situated over the first conveyor belt section and keeping the washing solvent for the downstream section in optimum condition.
At the end of the run of the last conveyor belt, there is a drying machine, preferably an air drying machine, which generates a flow of air fed by a suitable air-compressing generator. The drying machine is advantageously made up of the necessary pipes and diffusers which circulate a fixed flow of pressurized air over the scrap moving along the conveyor belts.
The speed of the process as well as the temperature of the solvents and the nature of the same depend on the characteristics of the solvents and the properties of the scrap itself. The variables can be modified by manipulating a control panel of the present invention.
Also subject matter of the present invention is a process for washing scraps of fibrous materials, wherein the scraps are fed in a closed hollow container and washed with at least one solvent spray and finally dried within the container.
Preferable steps of the process include: circulating the scraps inside of the container on at least one conveying belt; collecting the resin-loaded solvent, advantageously under the conveyor belt or belts, and re-circulating it to the spraying means; circulating the scraps along a plurality of washing sections each having its own solvent source tank; transferring the resin floating on the surface of the solvent in the solvent tank of a downstream section to the solvent tank of an upstream section; and detecting the loss of solvent in the container, in any washing section, and adding clean solvent to set the solvent quantity to a predetermined value.
The machine and process of the present invention are capable of separating the thermostable matrix and/or the reinforcements of fibrous scraps including, for instance, fiberglass, carbon fiber, polyamide, or similar materials impregnated with the resin, the toxic waste generated being made inert to a satisfactory degree and the possible subsequent re-use of the thermostable matrix as well as the reinforcements existing in the scraps. Moreover, the machine and process enable the amount of thermostable matrix contained in the final waste from the manufacturing process to be reduced.
The invention can be used in those industries involved in the manufacture of machinery to be used in industries dealing with the manufacture of components and machines with fiberglass, carbon fiber, polyamide staple, or similar materials, as well as in those activities related to the manufacture of machinery to be used in the recycling of industrial waste.
The invention can be suitably designed to ensure the total or partial recycling of the fiberglass, carbon, polyamide, or similar scraps impregnated with resin, thus leading to the recovery of a thermostable matrix and/or reinforcements made up of fiberglass, carbon fiber, polyamide staple, or similar materials, and likewise causing toxic waste generated during the manufacture of components and machines with these materials to be made inert and during the reduction of a thermostable matrix into fibrous materials.